OBJECTIVE: To define standards for normal endothelial function in adolescents by high-resolution ultrasound measurement of endothelium-dependent vascular dilatation. METHODS: This was a cross-sectional, descriptive, observational study and part of the thematic project "Clinical Study of Growth, Behavior, Arterial Hypertension, Obesity and Oral Health" (ECCCHOS) that was developed by the Discipline of Nutrition at the Universidade Federal de São Paulo. Thirty-one adolescents, eight male and 23 female, with no risk factors for systemic arterial hypertension were selected from 1,420 high school students. The students were daytime pupils at a school in the southeastern district of the city of São Paulo, the capital of São Paulo state, located in the Southeast region of Brazil. All results are presented in the form of means with standard deviations and percentiles. RESULTS: For male students, endothelium-dependant dilation 90 seconds after the cuff was released was 20.9±6,7% [mean ±1 standard deviation] with a 10th percentile of 12.5 and for females these figures were 18.8±12.9% with a 10th percentile of 6.6%. Values for the whole group of subjects were 19.3±11.7% and 6.7%, respectively. CONCLUSION: Endothelium-dependant vascular dilation of 6.7%, after 90 seconds, which corresponds to the 10th percentile, can be considered the lower limit of normality for this age group. Knowledge of this limit is important for the diagnosis of endothelium dysfunction that appears before cardiovascular disease.
Adolescents; endothelium; ultrasound
